EP0080427A2 - Tool for opening oysters or other similar bivalve shell molluscs - Google Patents

Abstract

1. A tool for opening oysters or other similar molluscs with bivalve shells, comprising a handle (1) provided at its end with a working head (2) including a means for spreading apart the valves and a means for dividing up the holding muscle of the valves, said toll being characterized in that the handle (1) has an elongated shape, in that the means for spreading apart the valves is a fixed means for dislocating and spreading apart the valves by the hinged portion of the shell, consisting of a lengthening piece (3) including a base (3A ) fixed in the handle and a free portion (3B ) having a tapering and pointed end (3C ), and in that the means for dividing up the muscle is a mobile element with longitudinal displacement consisting of a cutting means (5), such as a blade, which may be retracted into the handle and slides on a plane passing to a level situated between that of the base (3A ) of the lengthening piece and that of its end (3C ).

Description

The present invention relates to the opening of oysters or other similar bivalve shell molluscs for consumption.

In the following, reference will be made for convenience to oysters, it being understood that the invention is not limited to this example, but applies to any mollusc "with a bivalve shell", such as meats, scallops, etc. We mean by this expression to qualify any shell constituted by an edible body enclosed in a shell with two valves applying closely against each other. In the case of oysters, the valves are hinged together at one end, called "heel", by a ligament hinge and are held closed by a powerful muscle which connects them to each other in a slightly eccentric place towards the end opposite the heel and offset to the right, the oyster being seen from above.

Any operation to open oysters for consumption ends up cutting the restraining muscle. To achieve this, the scalers generally use a small knife with a sharp blade. This same instrument, on the other hand, becomes practically ineffective and, moreover, dangerous when it is used for the same purposes by an occasional operator, such as consumers.

It is indeed a question of forcing the blade into the joint of the valves in the vicinity of the muscle by exerting on the knife an effort in the direction of the oyster, therefore also in the direction of the. hand holding it. The accident generally occurs at this time there, following a shifting of the blade on the shell, following an error in detection of the joint, difficult to discern for an untrained eye in particular because of the very animated aspect of the leafing of the shell in the place considered.

Known oyster openers intended for the general public, some of which are widely distributed in the trade, all aim, more or less, to improve operator protection, but none is really satisfactory.

We can schematically classify them into two categories according to the method used to manage to penetrate the shell by a cutting organ intended to cut the muscle.

The instruments of the first category, derived from the knife for flaking, are used to dislodge and then to separate the valves using a blade that is tried to forcefully push into the joint to reach the muscle.

Among these are the common commercial utensils, such as knives with a broad and pointed blade, provided, at the right of the working end of the handle, with a guard for protection against slipping of the blade on the shell. In fact, the guard only properly protects the hand which holds the knife and which in any case risks only scratches when coming into contact with the shell, unlike the other hand which, holding the oyster, is exposed directly to the knife blade.

We also thought of garnishing the hand holding the oyster with a protective glove. However, the inevitable rigidity of the glove penalizes the ease of the opening operation in favor of operator safety which, moreover, remains limited.

The instruments of the second category proceed. ,, no longer by spacing the valves, but by removing a portion of the shell in order to provide an opening through which a cutting element is then introduced to cut the muscle. The material can be removed, either by cutting the end opposite the heel using a pair of cutting pliers (French Patent Application No. 1,536,939), or by punching a tablet on the upper flat valve in the immediate vicinity of the muscle using a tubular punch in which slides a sectioning wire by rotation (French Patent Applications No. 2,173,803 and 2,383,635).

In addition to the drawbacks linked to operating difficulties or to the questionable aesthetics of oysters opened under such conditions, these devices do not seem likely to ensure the essential cleanliness of the edible body with regard to debris or shell fragments which cause it. would make it unfit and even dangerous for consumption.

We know, on the other hand, a device common to the two above-mentioned categories in the sense that it intervenes by dislocation and gap valves in the vicinity of the muscle using a penetrating organ, distinct from the sectioning element of the muscle.

This device, described in French Patent Application No. 1 464 856, consists of a handle fitted with a working head provided with a short blade placed next to a motorized conical spin. As the instrument is brought closer to the oyster, the spin ensures the progressive spacing of the valves during its introduction, while the blade, slightly back, cuts the muscle.

In fact, this instrument somehow combines the respective disadvantages of the two categories mentioned above.

Indeed, the difficulties of the initial positioning of the point of the tendril in the joint, and their often unfortunate consequences for the safety of the operator, remain intact.

In addition, the spinning tendril which penetrates inside the oyster can bring with it fragments torn off on the edges of the valves and, likewise, disintegrate the edible body, thus rendering it unfit to be eaten, or at least meet the oyster presentation criteria demanded by consumers.

In addition, the spin motor, as well as the transmission members are placed inside the handle, so that it constitutes more of a protective casing than a grip handle capable of meeting the ergonomic criteria attached to such a qualifier.

We therefore see, through this rapid analysis of the state of the art, that the "oyster opener" utensils intended for the general public show a real inability to properly and jointly ensure the antagonistic imperatives of ease shell opening, operator safety, and presentation of the oyster, both in terms of aesthetics and cleanliness of the edible body.

The purpose of the present invention is precisely to reach the best compromise between all these contradictory requirements.

Another goal is to achieve a robust, reliable, simple design and low cost.

Yet another object is to provide inexperienced people with a means of opening oysters which is easy to handle, associated with a simple operating mode.

With all these objectives in view, the invention relates to a utensil for opening oysters, or other similar bivalve shell molluscs, comprising a gripping handle of elongated shape, equipped at one end with a working head provided, d on the one hand, a member for disengaging and spacing the valves by the heel of the shell constituted by a tip having a base implanted in the handle and a free part whose end is tapered and pointed, and, on the other part, of a sectioning element of the muscle constituted by a cutting member, such as a blade, retractable in the handle and sliding, at least at the point of the end piece, at a level located between the base and the pointed end of it.

According to a preferred embodiment, the free part of the end piece has, in profile, a curved shape, directed upwards.

Preferably, the pointed end of this free part is bent towards the horizontal.

According to an advantageous arrangement, the free part at least has, in section, a concave shape.

According to another arrangement of the utensil, the blade is assisted by a return spring exerting a force which tends to keep it retracted in the handle, said spring preferably being housed in a pusher provided on the blade.

As will no doubt already be understood, the invention is based on the idea of opening the oyster according to an original operating mode, in which two distinct means participate, intervening one after the other. to ensure respectively and chronologically the dislocation and the spacing of the valves then the sectioning of the retaining muscle.

Unlike the rotary twist device mentioned above, the disengagement and spacing member is fixed while the sectioning means is movable, in a longitudinal translational movement.

The operating mode, within which the utensil according to the invention was specially designed, consists in dislodging the oyster by its heel and not in penetrating it laterally, in the vicinity of the muscle, as logically the first approach to the problem and as advocated, incidentally, most of the known solutions.

The inventors have realized, in fact, that the heel, in spite of the apparent robustness of the oyster in this place, constitutes in fact the point of greatest vulnerability of the shell and this because of the existence, at the level of the articulation of the valves, of a natural slit necessary to its proper functioning.

The tapered shape of the end of the tip has been specially designed to be able to pass through this slot and engage without significant effort in the joint by at least partially destroying the ligaments.

The desired spacing is then effected by a simple and easy movement of tilting the handle from top to bottom relative to the oyster and, in the opening thus provided, the blade. leaving the handle cuts the muscle passing between the tip and the base of the tip.

The blade must be both long enough to reach the muscle from the heel and short enough, so as not to obstruct the engagement of the tip in the heel slot.

In fact, these two requirements are only contradictory in appearance since the cutting of the muscle only intervenes in the terminal phase after dislocation of the heel, so that a retractable blade appears perfectly appropriate.

Furthermore, it is advantageous to make this blade slide in the handle, since the latter, being dimensioned to ensure good grip on the part of the operator, has a length which is largely compatible with even a very large stroke of the blade. In addition, such an arrangement allows the operator to adjust the useful stroke of the blade as necessary, depending on the size of the oyster to be opened.

On the other hand, the upward curvature of the free part of the end piece, in accordance with an advantageous characteristic of the invention, is produced, inter alia, so that the blade, passing between the point and the base from the mouthpiece, easily penetrates the oyster between the valves kept apart by the mouthpiece and reaches the muscle at a height level which depends on the degree of tilting that is printed on the handle when the heel is disengaged.

We will see in more detail below how this curvature of the tip further improves the conditions of use of the utensil by ensuring in particular its locking in the shell after dislocation of the heel.

Furthermore, in accordance with a preferred variant, the endpiece is of concave shape in cross section. The effect of such an arrangement is to facilitate penetration, by conforming to the semi-circular shape which characterizes the slit at the location of the valve articulation ligaments.

In addition, the concavity of the end piece, as well as its curvature, contribute to reinforcing its mechanical resistance, which must necessarily be of good quality, because the end piece, acting as a lever during the spacing of the valves, is therefore found subject to relatively large bending stresses.

Incidentally, the concavity allows the mouthpiece to play a receptacle role in which the various debris and dirt inevitably present in the articulation slot of the oyster gather.

It will be observed that the tip according to the invention is a means of dislodging and spacing the valves which, unlike the known means (in particular the rotary spin mentioned at the beginning), does not penetrate inside the oyster, but remains on the periphery of the cavity housing the edible body.

Under these conditions, the latter is neither soiled nor injured and therefore remains in a state of cleanliness and flawless presentation.

It should be emphasized that the utensil according to the invention, used in accordance with the operating method which is closely associated with it, is of a nature to allow the opening of oysters in optimal conditions of ease, safety and cleanliness.

In accordance with another preferred embodiment of the invention, the working head also has an extension in the extension of the handle, either on one side of the nozzle or on the other (depending on whether the utensil is intended for right-handed or left-handed) more advantageously on both sides. Preferably, this projection extends parallel to the nozzle.

This advance is intended to come into abutment against the palm of the hand holding the oyster and thus provide the operator with both great maneuvering precision in the engagement phase of the toe in the heel slot and a total control of the effort to be exerted.

It also constitutes an effective and reassuring protective guard. It is however not easy to describe in more detail this particularly original and attractive aspect of the oyster opener according to the invention. However, the operator will be able to fully realize this for himself when using the utensil for the first time, since he will naturally have to use the advance, as indicated above, in order to be able to perfectly control its maneuver.

• - les figures la et 1b sont des vues du dessus de l'ustensile, selon une réalisation de l'invention, et montrant respectivement la lame en position rétractée et en position complètement sortie;
• - la figure le est une vue de face de la tête de travail de l'ustensile représenté sur la figure la;
• - la figure ld est une vue en coupe longitudinale axiale selon le plan AA de la figure la;
• - les figures le et lf sont des:coupes en section droite selon les plans BB et CC respectivement de la figure ld;
• - les figures 2a, 2b et 2c illustrent le mode opératoire de l'ustensile pour ouvrir les huîtres;
• - la figure 3a est une vue en coupe longitudinale partielle selon.le plan DD de la figure 3b et montrant l'extrémité arrière de l'ustensile dans une réalisation différente de celles des figures 1;
• - la figure 3b est une coupe en section droite selon le plan EE de la figure 3a;
• - la figure 4a est une vue du dessus,partiellement arrachée, d'une troisième variante de réalisation;
• - la figure 4b est une vue en coupe axiale longitudinale selon le plan FF de la figure 4a;
• - la figure 5 représente, vu de dessus, un ustensile selon l'invention selon une variante à lame à deux branches;
• - les figures 6a et 6b sont des coupes transversales d'une cinquième variante de l'invention selon le plan GG de la figure 6c et le plan HH de la figure 6d respectivement;
• - les figures 6c et 6d sont des vues en section longitudinale selon le plan II de la figure 6a et le plan JJ de la figure 6b respectivement;
• - les figures 7, 8 et 9a représentent chacune, en coupe longitudinale axiale, une autre variante de réalisation du dispositif selon l'invention;
• - la figure 9b est une vue en coupe transversale selon le plan KK de la figure 9a;
• - la figure 10 est une vue générale éclatée d'un ustensile selon l'invention dans sa forme de réalisation préférée.

The invention will in any case be well understood and other aspects and advantages will appear clearly in the light of the description which follows, given by way of example and with reference to the plates of attached drawings in which:

• - Figures la and 1b are views from above of the utensil, according to an embodiment of the invention, and respectively showing the blade in the retracted position and in the fully extended position;
• - Figure le is a front view of the working head of the utensil shown in Figure la;
• - Figure ld is a view in axial longitudinal section along the plane AA of Figure la;
• - Figures le and lf are: cross-sections in cross section along the planes BB and CC respectively of Figure ld;
• - Figures 2a, 2b and 2c illustrate the operating mode of the utensil to open the oysters;
• - Figure 3a is a partial longitudinal sectional view according to the DD plane of Figure 3b and showing the rear end of the utensil in a different embodiment from those of Figures 1;
• - Figure 3b is a section in cross section along the plane EE of Figure 3a;
• - Figure 4a is a top view, partially broken away, of a third alternative embodiment;
• - Figure 4b is a view in longitudinal axial section along the plane FF of Figure 4a;
• - Figure 5 shows, seen from above, a utensil according to the invention according to a blade variant with two branches;
• - Figures 6a and 6b are cross sections of a fifth variant of the invention according to the plane GG of Figure 6c and the plane HH of Figure 6d respectively;
• - Figures 6c and 6d are views in longitudinal section along the plane II of Figure 6a and the plane JJ of Figure 6b respectively;
• - Figures 7, 8 and 9a each show, in axial longitudinal section, another alternative embodiment of the device according to the invention;
• - Figure 9b is a cross-sectional view along the plane KK of Figure 9a;
• - Figure 10 is a general exploded view of a utensil according to the invention in its preferred embodiment.

In all the figures, the same elements are designated by identical references.

It should be noted that the figures can advantageously represent in real size the utensil according to the invention for opening the oysters.

We will first refer to Figures 1 illustrating a first embodiment. The complete description which will be given thereof will make it possible to limit the description of the other variants to their particular aspects which differentiate them from each other or with respect to this first variant.

The oyster-opening utensil according to the invention comprises an elongated straight handle 1 which is thick enough to ensure good manual grip. This handle is equipped at one end with a working head 2 for opening the shell.

The working head is provided with: a metal tip 3 centered on the axis of the handle, symbolized at 4; a blade 5 retractable in the handle and slightly offset to the right of the end piece (when looking at the utensil from above); a lower transverse tongue 7 slightly recessed and a projection in the extension of the handle, consisting of two branches 6 and 6 'on either side of the nozzle.

Each of these elements is now described separately.

The tip 3 of concave shape, is firmly anchored in the handle by its base 3A. Its free part 3g, curved upward and narrowing to its tapered and pointed end 3 _C , gives it a general shape reminiscent of that of a beak.

The two lateral branches 6 and 6 'extend the handle forward by moving away from their base by a distance at least equal to the width of the heel of the shell in order to be able to engage the working head around it and thus allow the introduction of the end piece. These branches are also curved upwards by matching the curvature of the end piece 3 (FIG. 1d) so that the latter does not exceed the limits of the volume defined by the branches between them. Their end has, moreover, a rounded shape, to come, one or the other, to bear against the hand holding the oyster, allowing sustained pressure without risk of injury.

These arrangements make it possible, as will no doubt have been understood, to allow this advance 6, 6 ′ to play a secondary protective guard function by wrapping the end piece 3.

Thus designed, this guard makes it possible, without penalizing the visibility of the operator, to "mask" the tip of the mouthpiece, so that any injury to the hand holding the oyster is practically excluded, and this even assuming that shifting of the nozzle on the shell, following an operating error, is possible.

It should also be noted that the curvature of the tip also contributes to limiting the risk of injury. This curved shape is, therefore, in itself an accessory means of protection which advantageously completes the purely functional character of the end piece.

The lower transverse tongue 7 has been provided as a protective guard for the hand holding the handle. It further defines, with a second tab 8 provided at the other end of the handle, a location for the operator's hand in optimal grip and safety conditions.

The blade 5 is actuated by a pusher 9 sliding on the upper part of the handle hollowed out for this purpose.

In the example considered, the pusher is formed by a simple folding of the blade 5. The latter is visible from above and slides flat on the bottom of a recess corridor 10, wide and shallow, whose blanks 11, 11 ′ advantageously serve as guide ramps for the thumb of the hand which drives the pusher.

The blade is extended at the rear of the pusher by an enlarged bending 12, the edges of which, engaged in the grooves 13, 13 'formed for this purpose at the base of the blanks 11, 11', provide both guidance in translation of the mobile assembly and its maintenance in position in the bottom of the corridor 10.

On the other hand, the blade is provided with a cutting edge 14 on the inner edge only to reduce the risk of injury. For the same purpose, its end is rounded in shape. The latter also has a small boss 15 on its upper face, the utility of which will appear later, with reference to FIGS. 2.

It should be observed that, seen from above, the blade 5 can be shifted to the right or to the left of the mouthpiece 3 However, in the case of oysters, the shift to the right is preferable, because the blade can then reach more easily the valve retaining muscle which is precisely on this side.

With regard to the relative height position, it has already been said that the blade must slide at least in the vicinity of the end piece at a level passing between the base 3A of the end piece and its tip 3 _C. Preferably, for reasons which will also become more clearly apparent below with reference to FIGS. 2, the blade slides about 1 cm below the tip 3 _C. This arrangement is illustrated in FIG. 1c, where we see that a light 16, provided in the working end 2 for the passage of the blade 5, is distant from the tip of the endpiece by a distance, noted "h", about 1 cm.

We now refer more specifically to Figures ld and lf.

It can be seen in these figures that the blade 5 is assisted by a return spring 17 which tends to keep it retracted inside the handle 1. This spring, of the "helical" type, is housed in a blind longitudinal cavity 18 formed in the body of the handle and which extends to the immediate vicinity of the base 3A of the nozzle.

As can be seen, the spring 17 works in compression in a direction opposite to that of the outlet from the blade 5. For this purpose, the spring is biased by a pad 19 connected to the blade 5 by a control wire 20 which passes through axially the spring passing through the opening of the cavity 18 at the rear of the handle.

The spring is in fixed abutment on a part 21, in the form of a funnel, added in the opening of the cavity 18. This funnel - has a central passage aligned with the axis of the spring 17 for centering the wire 20. That -this joins the rear end of range 12 of the blade by conforming to the profile of the internal surface of the funnel, the shape of which is determined to impart a curvature to the wire which prevents any jamming and thus ensures correct functioning of the blade.

The fixing of the wire on the track 12 can be carried out by any suitable means. The example considered shows a fixing by loop. 22 (FIGS. 1a and 1b) engaged in the curved end 23 of the area 12.

By. elsewhere, a groove 24 for housing and guiding the wire is provided on the funnel 21 and a closure plate 25 is applied to the rear of the handle against the funnel 21. The fixing of the plate is ensured by a screw 26.

It is understood under these conditions, that at the time of the exit of the blade, the pellet 19 comes to compress the spring 17 and the energy thus stored is restored later to ensure the automatic return of the blade 5 in the handle.

It should also be understood that the presence of the return spring 17 is explained by the search for maximum convenience for the operator.

The "safety" aspect does not come into play here, since the blade could only be dangerous when the valves were dislodged. However, at this time, the blade 5 is necessarily retracted to allow the introduction of the tip 3 in the heel of the oyster.

Finally, it will be noted that a third lower tab 27 is provided in the vicinity of the guard 7 and whose facing face of the latter advantageously serves as a retainer for the index finger of the hand holding the handle when the thumb comes to actuate the pusher 9.

We will now describe, with reference to Figures 2, the manual of the utensil, which will highlight other advantageous aspects of the invention.

A hollow oyster has been shown diagrammatically at 28, seen in longitudinal vertical section passing through the heel, designated at 29.

We see at 30 the upper flat valve, at 31 the hollow lower valve, at 32 the joint plane of these valves, at 33 the ligament hinge at the point of articulation of the shell and at 34 the retaining muscle. The edible body has not been shown to avoid unnecessarily overloading the figures.

As already pointed out at the beginning, the heel of the oyster constitutes a privileged point of approach because the joint of the valves has a natural slit at this point 35 offering free access to the ligament joint 33.

At the start of the operation, the oyster to be opened is held flat in one hand, the hollow valve 31 being in contact with the palm and the heel 29 being directed opposite the thumb. The utensil according to the invention is held by the other hand, the working head of course being directed towards the oyster.

The pointed end 3c of the end piece 3 is then introduced into the slot 35 of the heel according to the position visible in FIG. 2a.

In some cases, the slit may be locally narrowed by a seal due to a protrusion of the upper valve. But it is easy to blow up this cover using the tip 3 _C of the nozzle which is introduced into the passage left available.

By pushing on the handle of the utensil, and at the same time imparting slight oscillatory or rotational movements to it, if necessary, it is easy and without great effort to introduce the end of the nozzle into the inside the oyster through ligaments 33, which are then sectioned, as shown schematically in Figure 2b.

The ease of operation at this stage is obtained thanks to the fineness of the tip 3 _C of the nozzle.

This facility is further improved if the portion 3 _B of the endpiece which widens after the tip is concave, since it then perfectly matches the semi-circular profile of the valve junction slot. These conformational peculiarities, which one can perfectly realize by observing an open oyster, have not been shown to avoid overloading the figures too much.

It then completes to dislodge the heel by tilting the handle down, which has the effect, as shown in Figure 2c, to raise the upper valve 30 and thus provide a sufficient opening to allow the blade 5 out of the handle come in the vicinity of muscle 34. The cut thereof is then obtained by imparting to the utensil a slight pivoting movement on the horizontal.

As can be seen, the opening operation using the oyster opener according to the invention is extremely simple.

• Le déboîtement du talon 29 par l'embout recourbé 3 engagé dans la fente 35 se trouve largement facilité grâce à l'abondance de matière à l'extrémité de la valve creuse 31 et qui, comme le montrent les figures, vient en avancée par rapport à l'extrémité de la valve supérieure 30.

In addition to the advantages already mentioned above, the following special features should be emphasized:

• The dislocation of the heel 29 by the curved end piece 3 engaged in the slot 35 is greatly facilitated by the abundance of material at the end of the hollow valve 31 and which, as shown in the figures, comes forward relative at the end of the upper valve 30.

This prominence constitutes a bearing surface for the endpiece which can thus be maneuvered as a lever in a particularly efficient manner.

Although not compulsory, the curved shape of the end piece nevertheless has a decisive advantage in the sense that the end piece in this case constitutes a lever with evolving action, perfectly adapted to the differentiated needs which arise during the disengagement operation and valve spacing.

In fact, at the start (FIG. 2b) the end piece bears on the lower shell 31 at a point A very close to the lifting point B on the upper shell 30.

Then, during the rocking movement of the handle, as indicated by the arrow, the fulcrum runs along the contact generator of the nozzle and stabilizes at A 'at the end of the prominence of the heel (Figure 2c).

Thus, at the start of the operation, there is maximum leverage, precisely when it comes to overcoming the maximum resistance of the oyster resulting from the combined effect of the retaining muscle 34, from the sticking of the valves in the joint plane 32 and the residual traction of the filaments 33 not sectioned.

Then, by progressive increase in the lever arm BA, there is a spreading effect which is amplified, precisely when one seeks to provide a sufficient opening for the introduction of the blade and that the oyster n opposes more than a resistance limited to that of muscle 34 which, moreover, becomes more and more distended.

In addition, the curved shape of the end of the endpiece allows it to marry, during its introduction, a nipple 36 of the upper valve on which the ligaments 33 are fixed and which ensures the articulation of the shell by cooperating with a corresponding bowl (not shown) on the lower valve.

During the separation, the tip 3 _C of the end piece gradually takes position behind this nipple (Figure 2c), which then serves as a locking stop preventing any possible escape of the utensil.

Furthermore, this nipple should not constitute an obstacle to the passage of the blade 5, it is understood that the latter must slide at a level located below that of the tip 3 _C of the nozzle.

The minimum offset to be observed of course depends on the size of the nipple, but experience shows that a shift of the order of 1 cm is practically suitable in all cases.

The blade 5 thus passes in the vicinity of the nipple 36 and the boss 15 provided at its end ensures, if necessary, its sliding on the internal wall of the upper valve.

It is understood that the opening takes place, under these conditions, in an extremely advantageous way since, on the one hand, the blade practically does not attack the edible body of the oyster and, on the other hand, comes to cut the muscle 34 at its upper part by means of a simple horizontal movement of movement, which can be repeated several times in succession if necessary.

We thus recover all of the edible substance and the presentation thereof is perfectly assured in terms of aesthetics.

The second variant embodiment, illustrated in FIGS. 3a and 3b, consists in replacing the compression spring 17 by a tension spring of the "spiral" type with wound ribbon 37 with floating axis housed in a chamber 38 formed at the free end of handle 1.

The blade plunger, shown at 39, is, this time, an added piece.

At the same time, it provides the mechanical connection between the blade and the spring.

To this end, the pusher 39 has two lower pins 40 and 41 on which the end clicks respectively. mite of the blade 5 and the end of the spring 37 provided with openings for this purpose.

This variant has the advantage of minimizing the size of the spring, so that it becomes possible to implant the base of the end piece in the handle 1 as deeply as desired.

In addition, the choice of a spring of the “rolled ribbon” type has the advantage of keeping the force to be exerted on the pusher substantially constant during the output of the blade.

A third variant, illustrated in FIGS. 4, consists in making use, this time, of a compression spring 42 of the "accordion blade" type.

The mechanical connection with the blade 5 is effected by means of a bearing 43 produced by folding at a right angle to the end of the rear shelf 12 and which, in the rest state, abuts against the plate closing 25.

Unlike the variant shown in Figures 1, the spring is here biased in compression in the same direction as that of the blade outlet and its housing 44, open on the top, occupies almost the entire rear half volume of the handle.

In such a variant, the same advantage is found as in the case of the wound ribbon spring as regards the uniformity of the force to be exerted on the pusher 9.

FIG. 5 illustrates a fourth variant which relates, this time, to a particular embodiment of the muscle cutting blade.

'This blade, referenced 45, is cut into a "V", the two cutting branches 46 and 46' of which slide on either side of the end piece 3.

A blade of this type helps facilitate cutting of the muscle.

However, its production is slightly more complex than the blade 5 seen previously and this aspect can be taken into account in a study of manufacturing cost.

The fact remains, however, that the blade with two branches 45 is substitutable for the blade 5 and can therefore, in particular, be applied to all the variant embodiments which are described here.

A fifth variant is illustrated in FIGS. 6a to 6d. The detailed representation given by these figures is explained by the fact that the embodiment considered seems to correspond to a very competitive manufacturing cost for a utensil providing all the guarantees of reliability and robustness.

• - d'une part, l'embout 3 a été légèrement excentré latéralement par rapport à l'axe 4 du manche 1,
• - d'autre part, le ressort de rappel 47 utilisé est un ressort hélicoïdal à spires non jointives, similaire à celui retenu pour la variante des figures 1, mais son travail en compression s'effectue cette fois dans le même sens que celui de sortie de la lame 5.

This variant is essentially characterized by two originalities:

• on the one hand, the end piece 3 has been slightly offset laterally with respect to the axis 4 of the handle 1,
• - on the other hand, the return spring 47 used is a helical spring with non-contiguous turns, similar to that used for the variant of Figures 1, but its work in compression is carried out this time in the same direction as that of output blade 5.

The offset of the tip 3 provides greater availability of space in depth for the housing 48 of the spring which, as can be seen, can then extend practically over the entire length of the handle.

This feature has the advantage of being able to retain the benefit of a gentle and practically constant effort on the pusher 9 during the exit of the blade.

The spring 47 is stressed in compression by a pellet 49 resting at rest against the closure plate 25 under the effect of the residual pressure of the spring. This patch is connected to the end of the area 12 of the blade 5 by a tab 50 which slides in a slot 51 provided for this purpose in the bottom of the corridor 10. The patch and the tab can advantageously be produced by cutting and folding at right angles to the end of the rear shelf 12 of the blade.

It is understood that the slot 51 puts the spring housing in communication with the outside. However, the sealing of this housing, with respect to dirt and various debris, is ensured in a quasi-perfect manner thanks, on the one hand, to the narrowness of this slot and on the other hand and above all, to its location under the blade 5 which thus serves as a cover.

It will be noted that this particular location of the slot under the blade simply follows from the fact that, the nozzle 3 being offset laterally on the working head 2, the housing 48 of the spring is placed by construction under the blade 5.

FIG. 7 shows a sixth variant making it possible to reconcile a deep anchoring of the end piece with a return spring extending over the entire length of the handle.

For this purpose, it is the end piece 3 itself, or more precisely its base inserted in the handle 1, which serves as a housing for the spring.

The endpiece is centered on the axis of the handle 1 and has a base 3A practically as long as the latter and whose concave profile in "Ù" is significantly sharper than in the examples described above.

The end piece 3 is firmly anchored in a rectilinear groove 53 provided for this purpose on the bottom of the slide passage 10 of the blade 5, and the spring 54 takes place between the branches of the "U" profile.

The spring housing being here left open at its upper part, the spring 54 used in this embodiment is of the "traction" type in order to avoid the risks of ripples that a "compression" spring would pose in this case. The spring 54 is kept fixed at its rear end on the closure plate 25. It is stressed in tension at its other end by a small tongue 55 produced in "punctured" on the blade 5 itself, in front of the pusher 9 .

A seventh variant is illustrated in FIG. 8. Its originality resides in the fact that the support tab of the index finger to the right of the underside of the handle 1 (referenced 27, FIG. 1) here constitutes a trigger 56 mounted sliding in the handle and controlling the output of the blade 5.

₁ This slides in a recess formed this time by the underside of the handle 1 and has, in the vicinity of the underside thereof, a return 57 whose end is fixed to the trigger 56. A coil coil spring non-contiguous 58 is housed above the return 57 and its movable end bears against a shoulder 59 of the trigger which urges it in compression in the opposite direction to that of the blade outlet.

An eighth variant is shown in Figures 9a and 9b.

This achievement is rigorously based on both functional and constructive considerations.

In the case of a coil spring, that it is stressed in compression or traction, it is necessary, given the large stroke of the blade, to provide inside the handle a housing of great depth for the spring.

If the handle is produced by molding - as is advantageously the case - obtaining housing for the spring requires the presence in the handle of a sliding mandrel of great length.

Under these conditions, one obtains a handle 1 as shown in FIGS. 9, completely hollowed out axially and whose recess considered 60 passes to a level lower than that of the implantation of the end piece 3 to lead to the working head. 2 through an opening 61.

This produces a handle with a minimum of material, easy to produce in large series and whose housing 60 for the spring largely meets all the functional constraints related to the stroke of the blade.

It is therefore advantageous to use a "traction" spring 62 which, unlike the "compression" spring of the same type, accommodates a housing 60 of any shape which does not necessarily fit the template of the spring.

As can be seen, the spring 62 is fixed at one end to a plug closing the opening 61.

Its movable end is connected to the blade 5 according to the same principle as that of the variant shown in Figures 1, that is to say using a wire 20, guided by the funnel 21 attached to the rear opening of the handle, and the portion of which inside the housing is of course at least equal to the stroke of the blade.

The wire 20 is attached to a small tongue 64 made in a "punctured" on the blade 5.

The variant illustrated in FIG. 10 represents the best embodiment that the inventors know how to make at present.

It is characterized by the presence of a return spring 65 in the pusher 66 which actuates the blade 5.

These three elements are detailed below.

The pusher 66 has a cross section in the shape of a "T" intended to slide in the passage 10 of the same shape in the upper part of the handle 1.

The base of the pusher, which is preferably made by molding, comprises two cavities: a cavity 67 opening onto the front face and serving as a housing for the blade 5, the other, visible at 68, opening onto the lateral face of the base and serving as a housing for the spring 65.

The upper face of the pusher has an ergonomic wavy and ribbed shape to facilitate actuation by the thumb.

The return spring 65 is of the "spiral" type with preformed wound ribbon. Its outer end is folded in the opposite direction from the winding to form a small anchoring loop 69 which is housed in a small cavity 70 provided for this purpose at the rear end of the handle at the base of the blank 11 opposite the opening of the housing 68 of the spring.

The spring 65 has a small width and its size is slightly less than the volume of its housing 68.

The spring 65 is placed flat in its housing, so that its winding axis is vertical. Furthermore, its outer terminal part exits towards the rear end of the handle by passing through a small notch 71 provided for this purpose on the lateral face of the base of the pusher, and connecting the rear face 72 of the latter to the housing 68 .

Under these conditions, the spring unwinds while remaining practically invisible, the part of the unrolled ribbon pressing naturally and without curling against the side wall of the base of the corridor 10-.

The blade 5 for cutting the muscle advantageously has a small width over its entire length. Its rear end which fits into the cavity 67 can include sawtooth notches for example, intended to perfect its locking.

It is fixed by interlocking and / or by gluing.

It can also be made integral with the pusher 66 at the time of molding, according to the overmolding technique.

A closing plate 73 is provided for closing off the rear end of the handle by taking place in a centering counterbore 74. The fixing of the plate is ensured by a screw 75 engaged in the material of the handle.

As can be seen, the plate 73 has at its upper end a narrowing 76 wound forward.

This part 76 forms a loop which, when it is housed at the end of the corridor 10 serves as a stop for the pusher 66, in particular preventing any risk of injury.

It will be understood that this variant has many advantages, both practical and aesthetic as functional. Note in particular the reduced number of constituent elements. Their assembly, which takes place in the manner of a construction set, is rapid and therefore inexpensive.

It goes without saying that many other variants can be envisaged without departing from the scope of the invention as defined in the appended claims.

This is the case, in particular, with the shape of the projection 6, 6 ′ of the working end, which can vary over a wide range of conformational possibilities insofar as it constitutes a means of intermediate contact between the hand holding the handle and the hand holding the oyster, allowing it to come to rest on the latter when the toe is introduced into the heel, and, incidentally, insofar as no tapered and therefore dangerous part of the endpiece (in particular the point 3 _C ) does not protrude outside the limits of the volume generated by this advance.

The structure with two branches 6, 6 ′ was retained in the examples described, because it makes it possible to fulfill this dual role, both functional and protective, with a minimum of material while remaining aesthetic and preserving maximum visibility at 'operator.

Likewise, the blade and the tip do not necessarily appear side by side on the working head. It is, in fact, possible to produce a utensil according to the invention in which the blade and the end piece are superimposed, in which case, the blade passes through the end piece in a horizontal slot made for this purpose in the latter. It must however. note that with an embodiment of this type, there is a priori fear that the blade will carry with it inside the oyster debris accumulated in the concavity of the tip during the initial phase of dislocation of the heel.

On the other hand, as mentioned above, the handle can easily be produced by molding plastic material. The different fixed parts projecting from the body of the handle, other than the end piece, can advantageously be molded in manufacturing and in the same material as the handle. The insertion of the base of the nozzle can then be easily carried out using the overmolding technique.

Furthermore, the manufacture of the handle can be further simplified.

For example, the longitudinal grooves at the base of the blanks on the upper face of the handle and in which the edges of the blade engage can be eliminated.

It is however preferable to keep them in the case of the variants described with reference to FIGS. 4 and 10.

Indeed, for the other variants shown, these grooves are mainly intended to clamp the blade to prevent its possible exit from above the handle.

In fact, it can be considered that this function is implicitly already ensured by the cooperation of other means, namely, the passage slot provided on the working head, which cooperates in this regard, either with the control pad of the spring coming in abutment against the wall of the spring housing (Figure 6), or with the connecting wire (Figures 1, 9) which, under the permanent action of the spring, exerts on the blade a force having a vertical component which keeps it pressed against the bottom of its sliding corridor.

In addition, multiple arrangements or improvements can be made to the alternative embodiments described with reference to the figures.

In this regard, the inventors have realized that it could be advantageous to bend the pointed end 3 _C of the curved end piece 3 horizontally, as can be clearly seen in FIG. 10.

This arrangement allows, in fact, a more natural penetration of the oyster for the operator, by the possibility which is offered to him of giving to the handle an inclination on the horizontal, weaker than in the case of a completely curved end (Figure 2a).

Likewise, the concavity which advantageously has the tip may not extend to the tip 3.

This can indeed remain flat without penalizing the ease of penetration, because it is sufficiently tapered and pointed to fit without difficulty in the articulation slot of the valves.

So again, it is recalled that the free Part 3 ₈ of the tip need not be curved in longitudinal profile.

In one embodiment, the utensil according to the invention may in fact comprise an end piece whose visible part 3 _B has a generatrix of rectilinear support on the prominence of the heel (see FIG. 2)

This visible part, concave or not, can be inclined upward relative to the longitudinal axis of the handle or even in the axial extension thereof.

As can be understood, multiple embodiments can be envisaged, in particular as regards the shape or the orientation of the end piece, provided however that the essential characteristics of the invention are respected, as formulated in the main claim below. attached.

These are summarized schematically, on the one hand, to a tapered and pointed shape of the tip and, on the other hand, to a relative orientation between the tip and the blade, so that the latter slides, at at least in the vicinity of the end piece, in a plane transverse to the free part 3 _B, that is to say in a plane passing between the base of the end piece and its tip, so as to allow the blade to be introduced into the opening of the valves kept apart by the nozzle.

However, other variants relating to various functional or constructive aspects can be implemented.

For example, in the case of the variant illustrated in Figures 1, it is quite possible, in order to reduce the depth of the compression spring housing, couple it to a coaxial tension spring, of the same structure but of significantly smaller size, and that is interposed for example, between the pad and the control wire. The same result can also be obtained, without this small spring, using an elastic control wire.

Likewise, the variant described with reference to FIG. 10 may very well be produced using a return spring 65 installed in the pusher, no longer flat, but vertically (horizontal unwinding axis).

In such a case, the pusher would be larger in height in order to accommodate the spring there.

Similarly, the return spring 65 could be housed in the rear part of the handle, as in the variant illustrated in FIGS. 3, but arranged flat and at the level of the corridor 10, so that its unwound part, anchored in the blade pusher, remains invisible by being pressed against the base of the corridor blank.

More generally, the characteristic of the invention according to which the blade is assisted by a return spring must be understood as including not only a spring, in the usual meaning of this term, namely a mechanical member with elastic deformation , but any means capable of exerting an antagonistic action, elastic or not, which opposes the movement that is imparted to the blade.

A person skilled in the art will however be perfectly aware that, in the current state of knowledge, a spring, of the kind used in the examples described above, therefore represents the means best suited to a device such as an oyster-opening utensil, according to the invention, intended for the general public.

Furthermore, although the latter was originally designed for the opening of oysters, it is clear that its field of use extends, as we have already said, to any other shell mollusc analog bivalve.

In addition, its implementation, which is both simple and robust, poses no uncontrolled problem and makes it an object suitable for mass production under entirely competitive economic conditions from elements and materials available at low cost in trade.

The utensil according to the invention, used in accordance with the operating mode which is closely associated with it, ensures that the oysters are opened with an efficiency, safety and cleanliness which currently seem unmatched.

If desired, the retractable blade can be provided with two differentiated cutting edges: a main cutting edge well sharpened on the inside edge of the blade and a more blunt accessory cutting edge on the outside edge to prevent any possibility of injury.

Likewise, it will be understood that the term "blade" used to describe the retractable organ as a cut of the muscle, must be understood in its general meaning as a cutting element.

Thus, this term covers, not only, a blade proper in everyday language, namely an elongated, flat, thin and sharp tool on a bank, but any other functional equivalent, such as a threadlike element, capable of being able slice tender flesh, like that which constitutes molluscs and in particular the muscles of oysters.

Furthermore, it is important to emphasize that the inventors have realized that it was possible to further significantly improve the ease of cutting this muscle, when, the cutting element being a blade (taken here in its usual meaning) that -This has a slight lateral inclination on the horizontal so that, the utensil being seen from above, the right edge of the blade is raised relative to its left edge.

This position makes it possible, in fact, during the horizontal pivoting movement intended to cut the muscle by the blade in the fully extended position, to effect this blade movement from the inside of the oyster outwards towards the muscle avoiding obstacles on the inner wall of the shell.

The inventors have been able to show that in this respect an inclination of the order of 30 degrees on the horizontal was perfectly suitable without these indications being limiting.

However, it remains possible to achieve a similar ease of cutting otherwise, but then practicing a greater spacing of the valves, therefore a larger movement of tilting vertically the handle of the utensil.

The utensil according to the invention is used either by right-handers or by left-handers.

It can be provided, as we have seen, with safe and non-annoying protections which eliminate the slightest risk of injury while making other safety measures superfluous, such as the use of a protective glove, for example .

The ergonomic shape of its handle provides excellent manual gripping and the simplicity of its handling, which does not require any particular dexterity, puts it within the reach of the greatest number.

The utensil, in this regard, has been designed to leave a certain freedom of initiative to the operator, whose maneuver he will adapt according to the shape and size of the shell he wishes to open.

The inventors wanted, in fact, to preserve such a faculty after having noted that an oyster (or a shell) "type", of shape and size representative of the whole of the species does not exist, at least as regards the definition of a solution ensuring the opening under the excellent conditions specific to the invention.

Claims (11)

1) Utensil for opening oysters, or other similar bivalve shell molluscs, comprising a handle (1) provided, at its end, with a working head (2) comprising a means for spreading the valves and a means for cutting the valve retaining muscle, utensil characterized in that the handle (1) is elongated, in that the. means for spreading the valves is a fixed member for dislodging and spacing the valves by the heel of the shell, constituted by a tip (3) comprising a base (3A) implanted in the handle and a free part (3 _B ) having one end (3 _C ) tapered and pointed, and in that the muscle cutting means is a movable element in longitudinal translation constituted by a cutting member (5), such as a blade, retractable in the handle and sliding in a plane passing to a level located between that of the base (3A) of the nozzle and that of its end (3 _C ). 2) A utensil according to claim 1, characterized in that the free part (3 _B ) of the end piece has, in profile, an upwardly curved shape. 3) Utensil according to claims 1 or 2 characterized in that the end piece (3) is of concave shape in section, at least on its free part (3 _B ) to its tapered and pointed end (3 _C ). 4) Utensil according to claims 1, 2 or 3 characterized in that its tapered and pointed end (3 _e ) is bent towards the horizontal. 5) Utensil according to any one of the preceding claims, characterized in that the working head (2) is also equipped with a projection (6, 6 ') in the extension of the handle and having a rounded end intended to come to bear against the hand of the operator holding the oyster. 6) A utensil according to claim 5 characterized in that said projection consists of two branches (6 and 6 ') arranged in the lateral extension of the handle (1) on either side of the nozzle (3), having between -a spacing at least equal to the width of the heel of the oyster to be opened and conforming to the shape of the profile of the end piece (3) so that the latter does not exceed the limits of the volume defined between the two branches. . 7) A utensil according to any one of the preceding claims, characterized in that the retractable blade (5) is assisted by a return means tending to keep it in the retracted position in the handle (1). 8) A utensil according to claim 7 characterized in that the blade (5) is provided with a manual pusher (66) sliding in the handle (1) and in that the return means is a "spiral" spring (65) housed in said pusher. 9) Utensil according to any one of the preceding claims, characterized in that the end piece (3) and the retractable blade (5) are arranged side by side on the working end (2). 10) A utensil according to any one of the preceding claims characterized in that the handle (1) and the working head (2) comprising the projection (6, 6 ') and the guard (7), are in one room. 11) A utensil according to any one of the preceding claims characterized in that the blade (5) has a lateral inclination on the horizontal so that, the utensil being seen from the rear, the right edge of the blade (5 ) is raised from its left edge.

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